Bag bottomer



L 1951 E. E. BURROUGHS 5 BAG BOTTOMER Filed Sept. 11, 1948 ll Sheets-Sheet 3L INVENTOR Eawm E .Bumlaucui Oct. 2, 1 E. E. BURROUGHS BAG BOTTOMER Filed Sept. 11, 1948 ll Sheets-Sheet 2 INV E NT'OR. EDWIN E.BURROUGH5.

BY wwlwg k. ATTORNEYS.

Oct. 2, 1951 E; E. BURROUGHS BAG BOTTOMER INVE NTDR.

ATTORNEYS ll Sheets-Sheet 5 I J EDWIN E BURRQLJGHSw BY UM,

||||.lll I I l I I {ll ||I Filed Sept. 11, 1948 Oct. 2, 1951 E. E. BURRQUGHS 2,570,047

BAG BOTTQMER Filed Sept. 11, 1948 11 Sheets-Sheet INVENTOR Eowm E .'BURROUGHS.

L; ATTORNEYS.

Oct. 2, 1951 E. E. BURROUGHS BAG BOTTOMER INVENTOR.

ll Sheets-Sheet 5 Eowm E BURROUGH5.

Filed Sept. 11, 1948 ATTORNEYS.

11 Sheets-Sheet 6 INVCNTOR Eowuu E. BURR BY WM. M

BAG BOTTOMER iucns, L m-romlavs.

Oct. 2, 1951 E. E. BURROUGHS Filed Sept. 11, 1948 m8 p r W l r NNN 8w v2 ham 2 NNN mom 8 m8 Oct. 2, 1 51 E. E. BURROUGHS BAG BOTTOMER l1 Sheets-Sheet '7 Filed Sept. 11, 1948 EDWIN E.BURROUGH5. BY

W LAI X M 1L ATTORNEYS.

1951 E. E. BURROUGHS 2,570,047

BAG BOTTOMER Filed Sept. 11, 1948 11 s t s t 8 INVENTOR ATTORNEYS EDWIN E. BURROUGHS BY WM Oct. 2, 1951 E. E. BURROUGHS BAG BOTTOMER 11 Sheets-Sheet 9 Filed Sept. 11, 1948 INVENTOR EDWIN E-BURROUGHS.

1951 E. E. BURROUGHS 70, 7

BAG BOTTOMER Filed Sept. 11, 1948 ll Sheets-Sheet l0 INVENTOLE EDWIN E.BURRQ JGHS BY WM-mk-1 M ATTORNEYS.

11 Sheets-Sheet Ilil E. E. BURROUGHS BAG BOTTOMER mmuml Q But UFM L \r -ml hulk Q ZUEO WOZU DZUU Oct. 2, 1951 Filed Sept. 11, 1948 INVENTOR Eowuv E. BURRO UGHS.

Patented a. 2, 1951 OFFICE BAG BOTTOMER Edwin E. Burroughs, Brooklyn,

N. Y., assignor to St. Regis Paper Company, New York, N.'Y., a

corporation of New York Application September 11, 1948, Serial No. 48,820

8 Claims. (Cl. 93-22) This invention relates to bag forming apparatus, and more particularly to apparatus for automatically forming the bottoms of bags such as multi-ply valve bags.

Apparatus of this type which has been proposed in the past for automatically acting upon the end of a bag tube to form a bag bottom, has been subject to certain disadvantages because of the heretofore necessarily slow speed thereof and the consequent low output. One of the reasons for this low output has been the manner in which the ba tubes have been advanced from station to station. This manner as employed in the past has, for example, compromised'movin the bag intermittently from one operating station to the next, usually by means of rol ers. This met od has proven unsatisfactory from many standpoints, particularly from the standpoint of speed above mentioned and the standpoint of lack of positive control over the ba tube as it progresses from one operatin unit to the next.

The absence of a master device for controlling the motion of the bag tube as it is pro ressively operated upon toform a bag bottom therefor. has res lted in a lo s of control of t e has n many instances, and has made it impossible synchronously to adiust'all of the various units, while running. which form the bottom.

Moreover, it has been impossible in apparatus of this type heretofore proposed to introduce changes in the phase relationships of the various units with reference to a master bag tube conveyor, whereby adjustments can be made in the operation of the individual units while the apparatus is running.

In machines of this type which advance bag tubes intermittently from one station to the next the following disadvantages may appear: misalignment oi. the tube as it moves through the machine; deformation of bag bottom and valve due to such misalignment; reduction 01 speed;

and the axes of the many rollers which advance the bag tubes must be correctly aligned to an exacting degree. otherwise one roller portion may advance one side of a bag faster than another roller portion.

According to the present invention, a method and apparatus are provided which will eliminate the above noted diillculties or minimize same to such an extent that they are reduced to insigniiicance.

Various further and more specific objects, features and advantages of the invention will more fully appear from the detailed description when the same is read in connection with the accompanying drawings. It is to be expressly understood, however, that the drawings are for purposes of illustration only and are not intended as a. definition of the limits of the invention, reference for this latter purpose being had. to the appended claims.

In the drawings.

Fig. '1 is a side elevation first half of the machine;

Fig. 2 is a side elevation of the remainder of the machine which is arranged in line with or adjacent to the portion shown in Fig. 1;

Fig. 3 is a top plan view of the portion of the apparatus shown in Fig. 1;

Fig. 4-is a top plan view of that portion of the apparatus shown in Fig. 2;

Figs. 5, 5a, 5b, 5c are enlarged views of consecutively situated portions of the apparatus as shown in Figs. 1 and 2, that is, the lefthand extremity of the apparatus shown in Fig. 5a is in contact with the righthand extremity as shown in Fig. 5, the lines :c-x, 11-11 and 2-2 upon each of these figures being respectively in contact with one another;

Fig. 6 is a detailed cross-sectional view of the apparatus taken substantially on lines til-4i of Fig. 2, and showing a sleeve applying apparatus, together with a bottom fold unit and related portions of the device adjacent thereto;

Fig. 7 is a view in front elevation with parts broken away taken on line l-'l of Fig. 3 show ing one of the bottom spreading or opening units;

Fig. 8 is a view partly in section and with parts broken away of the gear trains and control mechanism for the spreader fingers as shown in Fig. 7;

Fig. 9 is a sectional view with parts broken away taken substantially on line 99 of Fig. 7;

Fig. 10 is a side view of a power drive shaft assembly for communicating torque to the bottom spreader unit shown in Figs. 7, 8 and 9;

Fig. 11 is a sectional view taken along line ll-il of Fig. 10;

Fig. 12 is a side elevation partly in section of a sleeve forming and applying apparatus, and a bottom folding unit;

Fig. 12a is a top plan view of a pair of bottom folding shoes or formers which are employed for bending the sides of the bag bottom to close same;

Fig. 13 is an enlarged detailed top view of a portion of the apparatus for forming the sleeves which are applied by the sleever shown in Fig. 12;

Fig. 14 is a sectional view taken along line of approximately the 3 14-44 of Fig. 13 which illustrates a sleeve striker bar adapted for urging sleeves against the cutting edges shown in Fig. 13;

Fig. 15 is a sectional view taken along line I -I5 of Fig. 13 showing in detail a part of the sleeve forming device.

Fig. 16 is a perspective view of a bag tube having one end thereof bent at right angles and being acted upon by a pair of rotating suction arms which pull apart the opposite sides of the tube end in order to permit the insertion of spreader fingers shown here and in Figs. 7, 8 and 9;

Figs. 17a to 17h, inclusive, illustrate steps in the formation of a pasted bag bottom by means of the present invention;

Fig. 18 is a perspective view of a bag tube having the opposite ends thereof bent angularly at approximately ninety degrees to the body of the bag tube, this position being similar to that shown in Fig. 170; and

Fig. 19 is a detailed perspective view of one corner of a bag bottom formed by the present a sleeve valve therein, for example, the lower proximately the center thereof at 31c and urged toward a closed position by a spring 31d which is attached to member 31b and to an arm 31c, the latter, for example, comprising a portion of the link upon which jaw member 311) is pivoted. In order to facilitate the opening of the jaws, a lever is secured to the pivot shaft 310 and a roller 39 is mounted on the end of such lever and adapted to contact a cam, to appear below, which can force the jaws open against the pressure of spring 31d.

right-hand corner of the bag-bottom shown in Fig. 17h..

The form of the invention illustrated in the accompanying drawings, by way of example, comprises apparatus for operating upon the ends of a previously formed bag tube, preferably of the multi-wall variety, whereby automatically a closed and sealed bag bottom is formed on one end and the other end is closed and sealed with the exception of a bag valve. Of course, if desired one or both ends of the bag tube can be formed into a bottom with or without a valve.

Instead of intermittently advancing a bag tube from one operating station to the next, as has been done in the past, the apparatus embodying this invention employs a master bag tube conveying means having a. plurality of equally spaced bag tube gripping devices thereon by which bag tubes are successively grasped and continuously advanced to the various operating stations at a uniform but adjustable speed. A common power source is employed for driving not only the bag tube conveyor means but also all of ,the various units which act upon the bag .tube to form the bag bottom. Suitable means are provided, however, for altering the phase adjustments of certain of said units whereby they can be adjusted as desired while the apparatus is in operation.

The novel apparatus comprises, in the form shown, a pair of synchronously driven endless sprocket chains or belts having the above-mentioned plurality of bag tube grippers thereupon which are adapted successively to grasp bag tubes and pull same through the machine in a manner to appear more fully hereinafter. The bag tube grippers act in pairs, one gripper of each pair being mounted on each sprocket. chain. Each pair of grippers is automatically closed simultaneously to grip a tube. The tubes are consecutively and automatically advanced to the grippers by a suitable feeder mechanism (not As above mentioned, the grippers act in pairs to grasp the tubes, and suitable means are provided for opening simultaneously the grippers of each pair as the pairs are consecutively moved into a bag gripping position. Such means comprise for example a pair of-cams, one for each side of the machine. One of these cams is indicated at 40 (Fig. 5) and is so constructed and arranged that as each roller 39 rides thereupon, the spring 31d is overcome and the jaws of the gripper are temporarily opened. As each roller 39 rolls off of the .cam 40, a .bag placed between the gripper jaws is immediately clamped and withdrawn from the feeder and advanced into the machine for the formation of the bottom.

After the tube ends have been formed into bottoms in a manner to appear more fully hereinafter, the 'pairs of bag grippers are successively opened by means of cams 4|, one of which.

is shown in Fig. 50, which releases the bag and permits the removal thereof from the machine.

The main power unit for this apparatus is shown in Figs. 2 and 4 and comprises an electric motor 42 which is in communication with a main drive shaft 43 through the intermediary of suitable pulley and belts 44. In the form shown four V-shaped belts are employed for interconnecting a motor pulley 45 with a power drive pulley 46, the latter being keyed to said shaft 43.

Power is communicated to the sprocket wheels which move the sprocket chains 3|, 32 by means of a gear train, as shown in Fig. 2, comprising gears 41 and 48, respectively, upon shafts 43 and 49. The latter shaft has attached thereto a helical gear 50 which is in engagement with a second helical gear 5| upon a shaft 52.. The sprocket thus power is communicated thereto. The

. sprocket chains 3|, 32 along the upper runs thereof rest upon rails 53, 54, as shown in Fig. 6, and the lower runs of these chains rest upon rails 53a,

54a, respectively. The chains are pulled over these rails thereby preventing any saggin which might interfere with the fabrication of the bag bottom. In order to prevent a flapping or occasional arching of the chains 3|, 32 upon the upper rails 53, 54, top hold down rails 53b, 54b (Fig. 6) are provided which fit centrally over said chains. Rails 53b, 54b also serve the purpose of holding the hains. down when the bag grippers engage cams 40, 4!. Were it not for such top hold down rails the gripper rollers 39 (and associated lever arm) engaging said cams would urge the chains outwardly without positive gripper operation.

There appears below a discussion of certain of the units for operating. upon the tube and tube ends for forming bag bottoms.

Bag tube feeder Slitting unit Consider, for example, the operation upon a particular bag tube 55 (Figs. 3 and 17) which is grasped by a pair of the gripper devices 31 (Fig. 3) as shown at the left extremity of Figs. 3 and 5. The bag conveyor means thereafter move the bag tube 55 at a uniform rate into a bag slitting unit 56 (Figs. 1, 3 and 5). The function of the slitting unit 56 is to form the slits 55a (Fig. 17) in the bag 55. This is accomplished by means of a pair of rotating knives 56a, one pair for each extremity of the tube end. The rotating knives 56a are secured by means of suitable collars to a rotating shaft 51 (Figs. 1, 3 and 5), the angular relationship between each pair 56 being adjustable in accordance with the width of the particular tube. In the form shown. the

knives 56 are angularly separated by approximately 140.

In order to cut the slits 55a, it is necessary for knives 55a to cooperate with suitable grooved backing members 58 (Fig. 5) which are so constructed and arranged that they rotate in phase relationshipwith the knives 56a and provide a firm backing therefor to enable each knife to cut into the bag. The grooved backing members 58 rotate upon a suitable shaft 59 (Fig. 5), and the shafts 51, 59 for the knives and backing members, respectively, are geared together by suitable gears 60, 6|, respectively (Fig. 1).

As shown in Fig. 1, power is communicated to the slitting unit from the main power'shaft 43 by means of the following gear train: gear 62 upon shaft 43, gear 64 upon an intermediate shaft 65 and a helical gear 66 which is inengagement with said helical gear 6| keyed to the shaft 55. I

Helical gear 66 is mounted upon the intermediate shaft 65. Interposed in said intermediate shaft 65 is a suitable differential 68 which is controlled by a hand wheel 69. The diflerential 68 is interposed in this gear train for the purpose of making phase adjustments to the knives 56a and their backin members 58 in order to position the slits 55a at desired locations upon the tube ends. Such a phase adjustment of the knives 55a can be accomplished while the apparatus is in motion.

In certain types of bag bottoms the slitting thereof is not desired. Consequently the present invention is not limited to one having such a slitting unit.

Main scoring unit A main scoring unit next preferably is employed for forming score lines upon the bag tube in order to facilitate the bending of each tube end to a position substantially perpendicular to the body of the tube, for a purpose to appear hereinafter. Such a unit is indicated as at 10 (Figs. 1, 3 and 5). This unit consists of a pair of scoring rollers II, one roller for each extremity of the tube, each roller consisting of a thin disc having a periphery which is adapted for forming a suitable fold line as at 12 (Fig. 17b) one fold line in each extremity of the bag tube. Of course, only a single score line can be formed it desired.

Cooperating with each scoring roller H is a grooved backing roller 13 (Fig. 5) the groove of which is in alignment with the scoring disc.

The main score roller 1| is mounted upon a cross shaft 14 (Figs. 1, 3 and 5) which may be geared to rotate with a shaft 15 upon which are mounted the grooved backing rollers I3.

Power is communicated to the scoring unit 10 from the said main'drive shaft 43 by means of a gear train comprisin a gear 16 upon shaft 43, which meshes with a gear 11 which in turn drives a helical gear 18, the latter engaging a helical gear 19 which drives the above-mentioned shaft 15. In view of the continuous and uniform periphery of the scoring rollers, it is not necessary to adjust their phase relationship to the other units of the machine. However, it is possible to adjust the axial position of at least one of the scoring rollers upon the shaft 14 whereby different sizes of bags can be accommodated. The spaced relationship. for example, of the upper scoring roller H, as viewed in Fig. 3, can be adjusted by conventional means, for example, by angularly adjusting a threaded shaft Ha having a bracket 1 lb threaded thereto, the latter communicating an axial thrust to said roller H by a yoke at one end thereof.

Tube end opener and spreader Novel means are provided for performing the preliminary opening and spreading operations upon the tube ends to prepare same for (a) the application of adhesive; (b) if desired, the depositing of a valve sleeve; and (c) folding and closing. Said novel means comprise:

(1) A so-called tube end bender" or rightangle bender for the tube ends which moves each tube end about the main score line to a position approximately at right angles to the main body of the tube. It is preferable to employ such a right angle bender as at 60 (Figs. 1, 3 and 5) because it positions the tube ends for easy cooperation with the elements for completing the tube end spreading operation. However, the invention is not limited'to such a bending device.

(2) A tube end opener as at 8! (Figs. 1, 3, 5) designed to cause a preliminary partial opening of the tube ends to facilitate the action of certain spreader fingers to appear below. The tube end opener opens each tube end as in Fig. 16.

(3) A tube end spreader as at 82 (Figs. 1, 3, 5, 7, 8 and 9).

Each of the above-mentioned units is discussed in detail below.

(1) Tube end bender.-In order to prepare each tube end for opening and spreading, it is desirable to bend same, as shown in Fig. 18, about the score lines 12 to a position approximately perpendicular to the main body of the tube. In such a tube end bending device shoe or former 83 engages the outer margin of a tube end and bends same from a position in alignment with the tube body into a position as shown in Fig. 18 substantially at right angles to saidtube body. A shoe or former 84 cooperates with shoe or former 83 for this purpose.

In order to accommodate tubes of differing lengths, the bending shoes 83, 84 can be spread apart or moved closer together by suitable conventional adjusting means.

(2) Tube end opener.-After the bag tube has been slit and the end thereof positioned, as shown in Fig. 18, said ends are prepared for opening and spreading. The preliminary step in the opening and spreading operations is shown'schematically in Fig. 16 and constitutes a partial opening by means of rotating suction arms having suction cups at the extremities thereof.

The tube end opening unit is indicated generally at 8| (Figs. 1, 3 and 5). One pair of the above-mentioned rotating suction arms is situated on each side of the apparatus for each extremity of the tube. One of these rotating arm suction units will now be described.

As shown in Figs. 3 and 16, a pair of rotating suction arms 85, 86 is shown comprising a pair of conduits having suction cups on the ends thereof, the conduits rotating one in a counterclockwise direction and the other in a clockwise direction. Conduit 85, in the form shown in Fig. 3, rotates in a clockwise direction and the other conduit in the opposite direction. These conduits rotate synchronously in such a manner that when the suction cups at the extremities thereof are closest one another, that is, when they are in alignment, the tangential components of their motions are in the same direction as the motion of the bag tube. rection of arrow 81 (Fig. 16). The two suction cups engage the vertical'part of the bagtube end and partially open it at the same time that it is moving forward in the direction of said arrow. When the bag tube end has been so partially opened, a group of fingers moving in synchronism acts thereupon in a spreading operation to be described hereinafter in connection with the above-mentioned spreading unit 82. The suction conduits, in. the form shown, move about substantially vertical axes and in arcuate paths in such a manner that by virtue of their angular motion and their engagement of the moving tube ends, partially open same.

The pair of suction arms 85, 86, as shown in Fig. 3 rotate in synchronous relationship because of a geared connection therebetween comprising a bevel gear 89, meshing with a bevel 98 which in turn drives the vertical shaft of the suction conduit 85. A bevel gear 9| is driven by the same shaft as in gear 89 and drives a gear 92 which in turn rotates the suction conduit 86.

Through a similar gear train the rotating suction arms 85a, 86a upon the' opposite side of the apparatus are geared for rotation in the same phase relationship as the pair 85, 8B. A horizontal shaft 93 (Fig. 3), extending across the machine is adapted for interconnecting the gear trains of the two pairs of rotating conduits.

A suitable device for creating a suction is em ployedwhich, in the form shown, comprises a conventional suction pump 94 (Fig. 1) which through suitable conduits is in communication with said suction cups.

As shown in Fig. 16, the suction arms 85a, 86a

I move toward one another and engage the moving tube end. Continued movement of the bag tube and further angular motion of the suction arms results in said partial opening of the tube ends.

The mechanism for communicating power to the rotating suction arms is shown in Fig. 1 and The latter is moving in the diis constituted by a shaft 85 which is keyed to the above-mentioned gear 11. The shaft 95, by means of bevel gears 88, communicates torque to said horizontal shaft 88 through the intermediary of another pair of bevel gears 98 (Fig. 3) and a vertical shaft 88 which interconnects said pairs of gears 88 and 88. In order to provide adjustment for the phase relationship of the rotating suction arms relative to the bag conveyor, a differential I08 is interposed in the shaft 95, having suitable manual adjustment means whereby desired corrections can be made in said phase relationship. Such a manual adjustment can be effected through a hand wheel Illl which controls one side of said differential.

The suction arm devices rest mainly upon two parallel stationary support shafts 93a, 9312 which extend across the machine. These shafts can act as rails upon which the two pairs of suction arms can be moved relative to one another for adjustments for bags of differing lengths.

(3) Tube end spreader.-The main function of this unit is to form the tube ends as shown in Fig. 17d whereby side andcorner flaps are spread into position. The corner flaps are also sometimes referred to as end flaps." This spreading .unit is also driven by the master power source, there also being aphase adjustment differential interposed in its power drive connection. The tube end spreader is indicated generally at 82 in Figs. 1, 3 and 5, and the details thereof are shown in Figs. '7 to 11, inclusive. Each unit comprises, as above mentioned, a plurality of.pairs of fingers which preferably are rotatable upon parallel shafts both driven from the common power source. The abov e-men-.

- tioned ro.atable suction arms rotate in a plane which is substantially horizontal. However, the spreader fingers rotate in unison in a plane which is substantially vertical in such a manner that certain of them reach down into the partially opened tube end and further spread the parts thereof, as willappear below. One pair of spreader fingers, designated the side flap spreader fingers, or primary spreader fingers first enters thepartly open tube end, the finger striking approximately at the mid point of the inner surface of the tube end. Said fingers are roLating in opposite directions in such a manner that they reach down into and spread out said tube end to form the above-mentioned side flaps by urging the side surfaces of the tube end downwardly and outwardly. Shortly after the commencing of the spreading of the side flaps a sec- 0nd pair of fingers also rotating in opposite directions (and upon the same shafts as said first mentioned pair) is inserted within the opened tube end and strikes same near the inner leading surfaces thereof, forcing same downwardly and outwardly, and forming a leading corner flap, effecting folds along a pair of diagonal fold lines which terminate at the inner extremities of the respective leading slits.

The second pair of fingers is termed the leading corner flap forming fingers. Means are provided for cyclically varying the speed of rotation of the shaft upon which the spreader fingers are secured, whereby, during each revolution, the

speed of rotation thereof is accelerated to a maximum during contact with the tube of said second pair of fingers. This insures insertion within the tube end of said fingers and a proper spreading of the forward corner flap. The speed of advance of the tube end makes it necessary so to speed up' the insertion of said second pair of fin- 9 gers whereby a so-called finger whipping action" occurs in order that the desired spreading action can take place before the tube end is moved out of range.

The shafts upon which said spreader fingers operate, continue to rotate whereupon, by the time of the completion of preselected angular movement the after corner portion of the tube end is in position for spreading. A third pair of spreader fingers mounted upon respective of said parallel shafts now is effective to engage the after corner portion of the tube end and to spread same, forming a trailing corner flap also having diagonal fold lines.

Referring now to Fig. 7, the operation of this unit in general is as follows: Situated above the bag tube conveyor means, on each side thereof, is a pair of parallel shafts I02, I03 which are parallel to the direction of motion of the bag tubes. Upon these parallel rotating shafts are mounted a left group of fingers and a right group of fingers, as viewed in said Fig. 7. The bag tube 55, also as viewed in Fig. 7, is moving away from us. The shafts I02 and I03 are moving in opposite directions, the former clockwise and. the latter counterclockwise, whereby the fingers can reach down into the opened tube end for spreading same.

From the left and right finger groups the following pairs of fingers are constituted:

(1) Side flap spreader fingers 104, 105.-The fingers of this pair, rotating in opposite directions, are adapted for reaching down into the partially opened tube end for providing the initial spreading action. These fingers initially strike the tube end preferably at or near points I08, I 01, respectively, as shown in Fig. 17d. The action of these fingers upon the tubeend is to spread outwardly the side flaps and thereby to provide an inward pulling action upon the corner flaps, in particular the leading one. Such side flaps are indicated in Fig. 17d at I and I05, and the corner flaps are indicated at H0 and III, the former being the leading corner flap.

(2) Leading corner flap forming fingers 112, 113.-The angular position of the leading corner flap fingers II 2, I I3 is preferably somewhat behind that of the pair I04, I05, that is, there is a slight angular displacement between these pairs whereby the second pair will enter the open tube end after the first pair, and will strike inside the leading corner flap preferably at or near points II 4, 5, respectively (Fig. 17d), which in the form shown are about five-eighths of one inch from their respective leading diagonal fold lines.

The angular velocity of fingers I02, I03 varies cyclically, as above mentioned, and reaches a maximum during the period that said fingers are in contact With said tube end, preferably at or shortly after the point of first contact. Fingers I02, I03 draw down thereove a portion of the leading corner fiap during a so-called finger whipping action which positively forms said leading corner flap and its diagonal fold lines as at 011, IIOb (Fighl'ld) before the tube end, by virtue of its forward motion, can move out of range.

Before fingers II 2, H3 become disengaged from within the tube end, the tube preferably enters between a pair of pinch rollers IIIia, II'Id (Figs. 5, 9) which assists in folding the now spread tube ends.

(3) The trailing corner flap spreading fingers 116, 117.This pair of fingers is so situated anflap III.

I gularly relative to the other two pairs that it will be in position to spread the trailing corner nap Ill (Fig. 17d) substantially Immediately after the spreading of the leading corner 1, The cyclical variation in angular velocity of the spreader fingers is accomplished, for example, by a pair of eccentric gears as shown at I18, 0 of Fig. 10. These gears are so arranged in the power drive gear train. of the spreader fingers that the angular speed of the leading corner flap fingers (H2, H3) is at its greatest when said fingers are acting upon the tube end. In other words, there is a rapid insertion and wiping action of these fingers as caused by the above-mentioned eccentric gears and thereafter a relatively slow angular motion and a subsequently quick or very rapid repetition of said wiping action. After the completion of the action of said pairs of fingers I04, I05, and III, N3 the third pair of fingers thereafter strikes the trailing corner nap III preferably at or near the points I20, Ill, res ectively (Fig. 17d.) and spreads same.

The spreader fingers are mounted upon their respective shafts, as shown for example in lug. 9 with respect to fingers I5, I I3 and III, by means of suitable adjustable mounting blocks "so, "3a and Illb, respectively. The angular adjustment of each of these mounting blocks, of course, can be varied in order to provide tne proper angular relationship therebetween to ac complish the spreading of said side and corner flaps. Said fingers I05, III and 1- preferably are threaded at the extremities thereof nearest the shaft I03 in order to permit insertion into suitable bores in said mounting blocks whereby a precise and fine control of their position relative to the bag tube can be obtained. Suitable means, such as bolts, can be employed for securing the fingers in the blocks firmly in their final adjusted positions.

Regarding the shapes of the fingers, reference is made to 7 and 9, with special reference to fingers I05, H3 and III which are illustrative. As viewed in Fig. 7, finger I05 is in the form of an L with the base thereof slightly curved. when finger I05 is in position mounted within its block I05a, it is seen that the threaded portion thereof is removedfrom the axis of its shaft I03 in such a manner that the rotatable portions, including both finger I05 and block I050, becomes in effect U-shaped. The fingers I00, I05, of course, are So constructed and arranged that when they are rotating, respectively, in clockwise and counterclockwise direction they are pointed downwardly into the open tube end at approximately the time of their first insertion into the tube end and thereafter will be inserted deeper, and will partake of a spreading and wiping action.

Regarding finger H3 (and its mate II2) as viewed in Fig. 7, this finger also is substantially L-shaped. However, as viewed in Fig. 9, it will be seen that the extremity of this finger is provided with a protuberance or arm "3?) which extends in the direction of motion of the bag 55. The function of this protuberance or extension is to permit or facilitate the spreading out of the leading corner flap whereby the flap will be drawn down over said protuberance. Thus the diagonal fold lines 011 and III!) will be more positively formed and will be prepared for in sertion into the pressing or pinching rollers 6a and la (Fig. 9).

With reference to finger I", one projection thereof as viewed in Fig. 7 is l.'-shaped as are those of the first two discussed fingers. In order to assist this finger in moving across the trailing corner flap II I, an angularly disposed elbow portion is provided as at II1c to which is attached an arm or extension id. The latter enables the finger to sweep over a wider area than ordinarily possible. If the angularly disposed elbow portion were not provided, it is possible for the trailing corner flap III to become bent backwardly in the wrong direction when it comes into engagement with the rotating finger Ill. The direction in which the protuberance II1d extends is in the direction of motion of the bag 55, as shown in Fig. 9.

As shown in Figs. 3 and 9, the spreader units 82 are mounted upon a pair of parallel support shafts I22 and I23 which extend across the path of the bag tubes and are mounted in suitable supports attached to the main frame 30 (Fig. l).

A description of the means for mounting the righthand unit82 will be given, it being understood that the lefthand mounting is analogous but adapted for the lefthand side of the machine.

Mounted upon said shafts I22, I23 is a housing I20 (Figs. '1, 8 and 9) within which is located the gear train for transmitting power from the main power drive to the shafts I02, I03.

The distance between both left and right spreader units 82 can be adjusted by suitable conventional means in order to accommodate bag tubes of varying lengths.

Supported between said shafts I22, I23 in suitable journals is a power shaft I26 which constitutes a part of the power transmitting mechanism from the main power source (motor 02) in a manner to appear more fully hereinafter. Shaft I26 also extends across the apparatus and is parallel to the shafts I22, I23.

Shaft I26, as shown in Fig. '8, communicates torque to the shafts I02, I03 and hence to the spreader fingers, through the intermediary of a gear train which has interposed therein a resilient member which gives to the spreader fingers a resilient touch" upon the bag tube end whereby a yielding engagement thereof is attained. This is necessary in order to avoid a tearing of the tube ends.

Referring to Fig. torque is transmitted to said shafts I02, I03 by means of the followin members: (1) a sleeve member I21, which preferably is keyed to the shaft I26. A key I210. is shown in Fig. 9 for this purpose. (2) Adjustably secured to sleeve I21 is an angularly adjustable collar member I28 (Figs. 8 and 9) having a bore therethrough adapted for fitting over one extremity of said sleeve I21, one extremity of collar I28 being clamped upon said sleeve I21 by means of a threaded bolt I20 (Fig. 9). At the opposite extremity of said member I28 is a protruding arm I28a (Figs. 8, 9) which is operatively connected to the remainder of the gear train through the intermediary of a resilient member such as a coiled spring shown in section at I30 (Fig. 8). (3) Said resilient member 130 is in engagement with a gear I3I by means of a stud member I32 which is secured thereto by means of a suitable nut and bolt I33. The stud I32 extends through an arcuate slot which is formed within a flange I21b of the sleeve I21. The function of the slot is to provide a bearing surface for the stud I32 to accommodate its angular motion which is caused by the flexing of spring I30. The spring I30 is compressed as a result of the fingers H2, H3 meeting with resistance when they draw down over themselves the corner fold I13. (4) The above-mentioned gear I3I is. in the form shown, of the helical variety which is adapted for transmitting torque to another helical'gear as at I32a. (5) The final gear of this gear train is a helical gear I330 which is in engagement with said gear I32a. and to which is attached the shaft I33.

Torque is communicated to the shaft I02 by means of suitable helical gears I30 and I33, as shown in Fig. 8.

A suitable double bearing I33 is provided for the shaft I02, as shown in Fig. 8, and a similar one is employed for the shaft I03.

It is necessary to provide means for spreading apart or bringing together the shafts I32, I03 to any desired position of adjustment in order to accommodate bags of varying sizes and tube ends of varying lengths having side and corner flaps of differing sizes.

Such means are shown in Figs. '1, 8 and 9, with particular reference to Fig. 7, and comprise a pair of angularly shiftable brackets I31, I30 upon which the shafts I02, I03 are mounted. Brackets I31, I33 are respectively mounted for angular movement about the center shafts I33, I00 of the helical gears I32a. I30.

The angular position of the brackets I31, I33 are controlled synchronously by a pair of worms and worm wheel segments, IOI, I02, respectively (Fig. '1). Worms IOI, I02 are mounted upon a common adjustment shaft I03 which is controllable by a hand wheel I00. The worms IOI, I02, of course, are in opposite directions in order that the brackets I31, I38 may be spread apart or,

moved closer together simultaneously.

In order to accommodate this angular movement of the brackets I31, I33, suitable arcu'ate slots I20a, I20b (Fig. '1) are cut in the housing I20.

When an adjustment is made by means of handwheel I00 friction normally may hold said brackets in adjusted position. However, vibration of the apparatus may upset this adjustment which makes it desirable to provide an additional locking mechanism for holding the brackets in a fixed position once an adjustment has been made. Such a locking mechanism for bracket I31 is shown as at I05 in Fig. '1. This mechanism communicates a clamping action to the bracket I31 in a conventional manner and clamps in position an arcuate slotted arm I03 (Fig. '1) rigidly secured to bracket I31.

A locking mechanism I01 is provided for bracket I38 which is adapted for cooperating with an arcuate slotted arm I08 in a manner analogous to mechanism I05.

Torque is communicated from the main drive shaft 03 to the shaft I20 (Fig.0) as shown in Figs. 1 and 10 as follows: An intermediate shaft I08 is operatively connected to the main power shaft 03 by means of suitable gears I53, IiI. Secured near one extremity of shaft I00 is a suitable helical gear I52 which is in mesh with a gear I53. The latter drives the lower press roller Illa (Figs. 5 and 9). The upper of these rollers IIIia is positively driven by means of a gear I50 which also is in mesh with the gear I33.

The shaft of roller IIIa is-indicated as at I50 (Figs. 5 and 10) and communicates torque to the above-mentioned shaft I23 through the intermediary of the gear train illustrated in Fig. 10. In Fig. 10 a pair of bevel gears I51 communicates torque from the shaft I53 to a vertical shaft I50 to which the above-mentioned eccentric gear H3 is secured. A parallel shaft I03 has secured therel3 6 to the other of the two eccentric gears Ill and the torque is thence passed to the spreader finger drive shaft I26 by means of a pair of bevel gears I66 (Fig. 10).

The action of the eccentric gears H8, H6, as explained above, is adapted to give the highest angular speed to the rotating spreader fingers II2, I II when they are actually in engagement with the tube ends. The angular speed of these fingers (H2, H3) is lowest when they are near the high points of their angular paths. Their angular velocity uniformly increases to a maximum during the down stroke and then uniformly decreases to a minimum. The point of maximum speed can be governed by adjusting the positions of the gears H8, 9.

In addition to the above-described adjustments to the angular positions of the spreader fingers by means of the handwheel I44, a diiferential I49a (Figs. 1 and 3) is interposed in the intermediate shaft I49 for the purpose of permitting adjustment to the phase relationship of said rotating fingers with the movement of the bag conveyor. A suitable handwheel I49b is provided for introducing such adiustment.

Pressing unit I62,I63 are driven by shaft I49 (Fig. 1) by means of gears I62a, I63a, the latter meshing with a gear I63b on said shaft I49.

Bottom fold line scoring unit Thereafter the spread tube end is subject to a fold line scoring unit which forms therein the bottom fold lines I64, as shown in Fig. 17c. This unit is a double scoring unit and determines the width of the bag bottom because upon the lines I64 the sidefiaps and portions of the corner flaps are folded over to form the bag bottom.

This unit is indicated in Fig. 1 at I65 and is constituted by two pairs of rollers roughly similar to the above-described main scoring roller 1I (Fig. 3), there being one pair of the double scoring rollers for each end of the tube. Asshown in Fig. 3, each pair comprises scoring rollers I66, I61 which are held in spaced relationship upon a rotating shaft I68. Thelatter extends across the machine and is rotated by means of a suitable gear train from the main power shaft 43 in a manner to appear below. The scoring rollers I66, I61 are adjustably mounted upon said shaft I68 and can be positioned in any desired spaced relationship by means of conventional collar locking devices. The distance between the scoring rollers I66, I61 determines the width of the final bag bottom because, as above mentioned, the folding thereof is effected along said bottom fold lines.

In view of the continuous and circular confirmation of the scoring rollers I66, I61, it is not necessary to introduce any correction to their phase relationship and consequently a nonadjustable gear train communicates power to these rollers. This gear train is illustrated in Fig. 1 and is constituted by gears I69 and I16 which communicate torque to a shaft "I to which is secured a helical gear I12. The latter is in mesh with another helical gear I13 which drives a shaft I14. Upon the latter shaft are mounted pairs of grooved rollers for cooperating with the main scoring rollers I66, I61. Furthermore, the gear I13 communicates torque to the shaft I68 by means of still another helical gear I15 which is keyed to said shaft I68.

Adhesive or paste applicator An adhesive or paste applicator is indicated generally in Fig. 1 at I16. This applicator is constituted by a pair of rollers I11, one pair to each side of the apparatus. As shown in Fig. 5a, the two cooperating rollers I11 rotate together by virtue of a gear interconnection which is formed by suitable gears I18, I19. Furthermore, the upper rollers I11 are provided with a so-called high segment for the purpose of communicating adhesive or paste to preselected edge areas of the corner and side flaps of the spread bag bottom. The shape of the paste applying high segment is identical with the shape of the area to which paste is applied, for example, as shown in Fig. 17!. The high segment" of the top roller I11 is adapted for applying the paste or adhesive in a conventional manner. In contact with the top paste applying roller is an intermedliate roll I which also is in engagement with a paste roll IIII, the latter being partially immersed in a bath of adhesive or paste. In order to spread a coat of adhesive smoothly upon the roll I8I, a suitable subsidiary or coat flattening roll I82 is provided (Fig. 5a). The paste roll I82 is intermittently shifted angular-1y by means of a suitable pawl and ratchet device I83 (Fig. 1), the pawl being driven by an eccentric I84 upon the shaft of the top roll I11.

Sleeve forming and applying mechanism Mechanism is next provided for forming a sleeve I66 (Figs. 17g and 19) and depositing same upon the spread tube end preferably adjacent the leading corner thereof, and thereafter folding the spread tube end along the above-mentioned bottom fold lines I64, to form a finished bag bottom as illustrated in Fig. 17h.

Such a unit is illustrated generally at I61 (Fig. 2) and is illustrated in more detail in Figs. 4, 5b, 6, 12, 13, 14 and 15.

A reel of paper is indicated at I68 (Fig. 2) from which the sleeves are formed in a conventional sleeve forming device. Sleeves are cut from the strip comprising said roll, formed, and grasped bya rotating drum I89, by means of suitable grippers, and deposited upon the pasted tube end in the positionshown in Fig. 179 above mentioned.

A web I88a of the paper is fed over suitable rollers 2) to a mandril or former I93. This mandril is also shown in Figs. 12 and 13. The web I880. is folded over said mandril under the action of a pair of rollers I94 and I95 which are preferably of a resilient material such as rubber and mounted upon pivoted arms I96 and I91, respectively.

An adhesive or paste is applied to one of the I88, as shown in Fig. 2, I96, I! and I92 (Fig.

edges of the web I88a by means of a sleeve seam paste applicator I98 (Fig. 2) whereby one of the edges of the web, as at I88b (Fig. 13) is provided with a thin strip of adhesive.

The web I 66a, after having been folded and pasted, as shown in Fig. 13, is pulled through the sleeve forming apparatus by means of a pair of rollers I99 (Figs. 12 and to which a torque is transmitted in a manner to appear more fully hereinafter.

After the folded sleeve has been drawnthrough therollers I 99, it is thrust into the cut-off" area 200 (Fig. 15) where a pair of cutting edges l, 202 are effective in combination with a striker arm 203 (Figs. 14 and 15) to sever the sleeve from the web, whereupon it is further pressed and grasped by the above-mentioned sleeve applying drum I89 (Fig. 2).

In order to form a sleeve I86, as shown in Fig. 19, having an overlapping leading edge I88a which hangs over the lower lip I88b thereof, the cutting tool 20I is of arcuate shape and is situated below the straight serrated cutting tool 202.

The striker arm 283 is rotated in timed relationship with the sleeve forming apparatus whereby it strikes the sleeve immediately beneath and slightly forward of the cutting edge 20I whereby the above-described overhanging arcuate leading edge I8Ba (Fig. 19) is formed. Thereafter the straight portion of the sleeve is formed by thrusting same against the cutting edge 202.

As shown in Fig. 12, a pair of sleeve gripping devices 205 are mounted diametrically opposite one another and adjacent the periphery of the sleeve applying drum I89. Grippers 205 are controlled, for example, by suitable cam devices which cause same to close and grasp a completed sleeve and pull it away from the sleeve forming apparatus, whereupon it is carried in the direction of the arrow and deposited upon the oncoming bag tube. Each gripper 205 is mounted upon a suitable shaft 206 having a, gear 201 secured thereto which is in engagement with a toothed segmental member 208 which is pivoted at 209. The segmental member 208 is urged in a counterclockwise direction by means of a spring 2l0 which thus urges the gripper 205 toward a closed position.

The gripper opening and closing control means is constituted by a cam 2 which is fixedly mounted and which is adapted for angularly shifting said segmental members 208 by means of an arm 2I2 having a roller secured to the extremity thereof. Said arms 2I2 are either secured to said segmental member 208 or rigidly attached to the pivotal mounting 209 therefor.

Only two sleeve gripping devices 205 are shown, one of these being adapted for gripping a sleeve which has been severed just prior to the time when a diametrically opposed sleeve is being deposited upon the bag bottom.

The sleeve applying drum I89 has two areas, I89a, I89b, upon the periphery thereof which are higher than the remainder of the periphery. The high portions serve the purpose of pressing downwardly the glued sleeve to the pasted spread tubeend. That is, the high portions I89a, I89b, are adapted for firmly aflixing the sleeve to the glued portions of the tube end, as shown in Fig. 179.

The sleeve gripping devices 205, as shown in Fig. 12, are diametrically opposed upon the drum I89. The sleeve gripper in the uppermost position (Fig. 12) has Just closed upon a sleeve in order to withdraw same from the sleeve forming device. The closing of the gripper occur by virtue of disengagement of the arm and roller 2I2 with the stationary cam 2| I.

The sleeve gripper 205 in the lowermost position in this figure is held closed under the influence of spring 2l0 and will so remain until its 18 opening arm and roller 2 I2 engages the lowermost portion of the cam 2| I, whereupon the sleeve will be released in the desired location (Fig. 17a).

The above-described rollers I99 (Figs. 13 and 15) preferably are constituted by one superposed pair on the left side of the sleeve and another ,pair on the right side. These pairs of rollers are in spaced relationship upon shafts I99a and I998. Each pair of superposed rollers I99 (Fig. 15) are adapted for gripping the sleeve and pressingsame directly therebetween without the interposition of any part of the mandril I93. The latter, as shown in Figs. 12, 13 and 15, is provided with a portion I93a which is substantially horizontal, and another upwardly slanted portion l98b which is in alignment with the oncoming paper web; The left-hand extremity of the horizontal portion I930, (Fig. 15) has formed thereon the above-described serrated cutting edge 20! for the formation of the arcuate overhanging portion I88a of the sleeve I86. Suitable indentations as at I930 are provided: on either side of the mandril in order to permit the rollers I99 directly to press between them the folded sleeve.

Rollers 2I3, 2, which are moved in timed relationship with the rotating drum I89 and the remainder of the sleeve forming apparatus, act as retarders to produce an arc in the paper web gtafvoid improper cutting against the cutters 20I,

Torque is communicated to the sleeve forming apparatus by means of the following transmitting mechanism: A gear 2I5 upon main power shaft 43 drives a shaft 2 I6 by means of a gear 2 meshing therewith. Shaft 2I6 drives a transverse shaft 2I'la by means of engaging helical gears 2I8 and 2I9, respectively. Upon the latter is mounted a roller 220 (Fig. 12) which cooperates with drum I89, whereby the sleeves are pressed upon the bag bottom. A similar roller 22I (Figs. 4 and 6) is mounted upon the shaft 2I1a on the opposite side of the machine to provide a backing for the pressing of a sleeve upon the, opposite bag bottom if so desired.

Central grooves 220a and 22ia are formed in the rollers 220, 22 I, respectively (Fig. 6), in order to accommodate the fingers of sleeve g'rippers 205.

As indicated in Figs. 6 and 12, the rotatable drum I89 is mounted for rotation upon a shaft 222, and said drum can be shifted from one side of the machine to another and clamped in a desired position. Suitable keying means are provided to facilitate such axial movement of drum I 89. Torque is communicated to the shaft 222 from the shaft 2Ila (Fig. 6) by means of shaft 223 and suitable bevel gears 224 and 225.

Torque is transmitted to the rotating striker arm 203 and to the rollers I99, 2I3, 2, as shown in Figs. 4, 6," 12 and 13, by means of a helical gear 226 which engages another such gear 221 which rotates upon a shaft 228 perpendicular to that of gear 226. Shaft 228 rotates within suitable journals as at 229, 230 (Figs. 4, 13). Shaft 228 is in operative engagement withthe roller 2 I9 by means of bevel gears 23I. Moreover, said shaft 228 has secured thereto a flange 232 to which is attached said striker bar 203. Fine adjustments to the position of striker bar 203 can be made by virtue of its mounting upon the flange 232 (Fig. 14). An arcuate member 233 is provided at the base of the striker bar for attachment to the flange 232, and arcuate slot 233a is formed in said member through which a suitable securing means, such as a bolt 234.

can be inserted for adjustably positioning the 17 striker bar, within the limits of said slot, about a pivot 235.

The rollers I99 are operatively associated with the roller 2 l3 by means of a gear train made up of gears 235, 231, 238 and 239 (Figs. 12 and 13).

Thus all of the rotating elements of the sleeve forming unit operate in timed relationship to one another and to the master bag tube conveyor.

Adjustment of the phase relationship of said bag tube conveyor and the sleeve forming unit can be made manually while the apparatus isin operation by means of a differential 2l6a (Fig. 2) which is interposed in said shaft H6 and which is provided with an adjustment hand- Bottom fold unit After the sleeve I86 has been deposited upon the spread tube end, as shown in Fig. 17g and therein pressed in place, the side flaps I08, I09 and portions of the corner flaps H0, III are folded along the side fold lines "54 to the position shown in Fig. 17h, whereupon the tube end is finally formed into a completed pasted bag bottom and may then be ironed or pressed.

The bottom folding mechanism is shown in Figs. 4, 6, l2 and 12a, there being one pair of bottom folding shoes or formers on each side of the apparatus, one for each extremity of the bag tube.

Referring particularly to Fig. 12a, one of the bottom folding units is indicated at 240 comprising an inner flap folding shoe 241 and an outer flap folding shoe 242. These shoes are mounted parallel, the areas first encountered by the bag bottoms as at 241a and 242a. being substantially horizontal. The inner margins or edge areas of the shoes 2, 242 remain horizontal and coplanar With the above-mentioned areas 24M, 242a. However, the outer margins of each shoe is formed so that it progressively folds over said horizontal inner edge, the folding over of shoe 24! occurring at 24".; and of shoe 242 at 242b, The point of complete folding of shoe 24! is in advance of that of shoe 242 in order to insure that the inner side flap I08 is folded over first whereupon the outer side flap is superimposed thereupon and prepared for final pressing.

Final bag bottom pressing unit The bag tubes having their bottoms folded.

as in Fig. 17h, next preferably are delivered to a bottom pressing unit indicated at 243 (Figs. 2 and 4). This unit is constituted by two pairs of rollers 244, 245 (upper and lower, respectively), one pair for each extremity of the bag. These rollers lightly press together the folded bag bottoms to insure a positive adhesion between the adhesive bearing portions of the bag bottom. The pressure is light to avoid expelling the paste.

Bag delivery unit Ill from left to right, as viewed in Fig. 5c, whereby the completed bag is delivered from the machine.

' Torque is communicated to the pressing rollers 244, 245 from the above-mentioned shaft 49 by means of a pair of helical gears 250, 251 (Fig. 2), the latter being in engagement with a suitable helical gear 252 for rotating the upper of the two pressing rollers 244.

The belt 241, being in engagement with the upper of the rollers 244, thus is put in motion to deliver the bags.

The operation of this apparatus has been described in connection with the individual elements above set forth.

There is thus provided novel means for forming the bottom of a bag from the bag tube. Bag tubes of the multi-layer variety can be successively operated upon by this apparatus, particular reference being had to bag tubes having so-called stepped ends, for example, as shown in the Patent 2,055,030, granted September 22, 1936. However, it is possible to form bag bottoms upon bag tubes having ends which are not similarly stepped and which have greater or less number of plies. The novel bag bottom forming apparatus is capable of a heretofore unattained output of about one hundred fifty bags per minute.

Although only one embodiment of the present invention has been illustrated and described in detail, it is to be expressly understood that the invention is not limited thereto. Various changes may be made in the design and arrangement of the parts without departing from the spirit and scope of the invention as the same will now be understood by those skilled in the art. For a definition of the limits of the invention, reference will be had to the appended claims.

What is claimed is:

1. In an automatic bag bottom forming apparatus, a bag tube conveyor, including spaced gripping means for consecutively gripping a plurality of bag tubes near opposite extremities along the leading edges thereof; and moving same in succession relative to said apparatus in preselected spaced relationship; mechanism for consecutively spreading a tube. end of each of the tubes moved by said conveyor and forming thereupon side and end flaps, said spreading mechanism including a supporting member mounted for rotation about an axis substantially parallel to the path of bag tube movement, such spreading mechanism thus being angularly shiftable upon such supporting member about such axis, means for mounting said spreading mechanism against movement in the direction of such path of bag tube movement; mechanism for applying adhesive consecutively to the spread tube ends upon a preselected area thereof; folding mechanism for acting consecutively upon the tubes for folding at least one side flap of each tube over another side fiap' thereof; and mechanism for operatively connecting said conveyor with said spreader and adhesive apply; ing mechanisms for maintaining a preselected phase relationship therebetween, said conveyor moving continuously the bag tubes in succession relative to said mechanisms. 2. In an automatic bag bottom forming app ratus, the combination comprising, a bag, tube conveyor; mechanism for moving said conveyon at a predetermined speed; mechanism gfQ pre liminarily opening the end of a bag tu is conveyed by said conveyor to facilitat the spreading of the tube end; a pair' of an arly shiftable side flap spreader fingers for rea ing, into the preliminarily opened tube 

